78817698709 has 2 divisors, whose sum is σ = 78817698710. Its totient is φ = 78817698708.

The previous prime is 78817698697. The next prime is 78817698733. The reversal of 78817698709 is 90789671887.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58251270609 + 20566428100 = 241353^2 + 143410^2 .

It is a cyclic number.

It is not a de Polignac number, because 78817698709 - 2¹³ = 78817690517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78817198709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39408849354 + 39408849355.

It is an arithmetic number, because the mean of its divisors is an integer number (39408849355).

Almost surely, 2^78817698709 is an apocalyptic number.

It is an amenable number.

78817698709 is a deficient number, since it is larger than the sum of its proper divisors (1).

78817698709 is an equidigital number, since it uses as much as digits as its factorization.

78817698709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 85349376, while the sum is 70.

The spelling of 78817698709 in words is "seventy-eight billion, eight hundred seventeen million, six hundred ninety-eight thousand, seven hundred nine".